Overview of High-Availability Features
High Availability (HA) is an implementation designed to maintain uptime and access to services even during component overloads and failures. Terracotta clusters offer simple and scalable HA implementations based on the Terracotta Server Array (see Terracotta Server Array Architecture for more information).
The main features of a Terracotta HA architecture include:
Instant failover using a hot standby or multiple active servers - provides continuous uptime and services
Automatic permanent storage of all current shared (in-memory) data - available to all server instances (no loss of application state)
Automatic reconnection of temporarily disconnected server instances and clients - restores hot standbys without operator intervention, allows "lost" clients to reconnect
Client reconnection refers to reconnecting clients that have not yet been disconnected from the cluster by the Terracotta Server Array. To learn about reconnecting BigMemory Max clients that have been disconnected from their cluster, see
Automatic Client Reconnect.
Tip:
Nomenclature - This document may refer to a Terracotta server instance as L2, and a Terracotta client (the node running your application) as L1. These are the shorthand references used in Terracotta configuration files.
It is important to thoroughly test any High Availability setup before going to production. Suggestions for testing High Availability configurations are provided in the section
Testing High-Availability Deployments.